PR #27884 - manaflow-ai/cmux

Leo, 2026-10-29: "why is there all this weird stuff at the bottom of the sidebar" / "a whole lot of this cloud stuff ought to get better...". Standing order the same day: "no new workspaces or terminals as side effects".

What was wrong

CloudService.reconcile connects every Cloud machine of the account that isn't destroyed, including the VMs agents and lane-pool tools make.
Each machine's daemon starts with a workspace from its image (bash in the home folder).
reconcileMembership collects every workspace of every daemon. WindowRegistry.reconcile gives each unowned one to the most recent window.
So every agent, lane-pool or test VM put a "cmux · ~" row and a bare home-folder row into the person's sidebar.
On top of that, cmux cloud new-machine from a tool without focus filed the new machine's first workspace into the active window (reveal).

Fix

Membership (WindowManager+Membership.swift): a Cloud machine's workspaces join a window only once the person has opened that machine here. Opened means one of its workspaces is in a window (open or closed) or claimed for one: Open Machine, New Cloud Workspace, a create with focus. Until then reconcile holds them (unopenedCloudWorkspaces), so they show in no sidebar. Opening the machine brings them in, and machines the person already uses behave as before.
Only a machine's own ids count toward "opened". A VM made from another VM's snapshot keeps its workspace keys, so a window holding the other machine's copy must not open this one.
Creation (CloudHandlers.creationFlow): a machine created without a window to show it in is filed (reveal) only when the person started it. An agent's or the CLI's cloud new-machine without focus leaves it out of the sidebar. With --focus it shows, as before.
No sidebar row or layout file changes. The row rendering (the gap, the header, the home title) is fixed in separate PRs.

Tests

Tests/CmuxNextAppTests/UnopenedCloudMachinesTests.swift, committed before the fix (3504896f274):

a fresh machine's image workspace joins no window and opens none
a machine that already has a workspace in a window takes new ones in
a workspace key shared with an opened machine does not open another machine
an agent's create files nothing; the person's create shows its workspace

Command: swift test --filter UnopenedCloudMachinesTests (CmuxNextAppTests, macOS). Expected red at 3504896f274 and green at the head. Results are posted below once CI runs.

Also adds the Debug capture scene cloud-agent-machines: two running Cloud machines, never opened here, each with its image workspace, for the before/after stills.

Observed

At 247c1f361fee879cd724ae0a0e111d25447b0c6b on a fleet Mac: CloudWorkspaceRestoreTests passed, UnopenedCloudMachinesTests passed.
Independent review: Sol SHIP at 247c1f361fee879cd724ae0a0e111d25447b0c6b (https://github.com/manaflow-ai/cmux/pull/27884#issuecomment-6537285252).

Before / after

Scene cloud-agent-machines at 2x, cropped to the sidebar. Before is d5fecc84 (base); after is the head.

	Light	Dark
Before
After

Viewed after image: yes
Visual verdict: the two never-opened agent machines' "workspace-1" rows are gone and the sidebar shows only the person's own workspaces, which reads cleanly next to ChatGPT or Claude.

Changelog

Fixed: Cloud machines that agents or tools create no longer add rows to your sidebar until you open them.

risk:normal

Agent session: agent session

🤖 Generated with Claude Code